RFR: JDK-8311035: CDS should not use dump time JVM narrow Klass encoding to pre-compute Klass ids [v7]

[Thomas Stuefe]

On Wed, 5 Jul 2023 05:23:43 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:
>> 
>>  - Merge branch 'master' into fix-cleanup-CDS-nKlass-encoding
>>  - revert accidental change
>>  - Fix Windows build
>>  - Add alternative for !INCLUDE_CDS_JAVA_HEAP path
>>  - Merge branch 'master' into fix-cleanup-CDS-nKlass-encoding
>>  - fix comment
>>  - Merge
>>  - -remove narrow_klass_xxx from FileMap
>>    - remove ArchiveHeapWriter::precomputed_narrow_klass_base_delta and replaced it with clear comments
>>    - changed runtime fail condition to asserts in FileMapInfo::can_use_heap_region()
>>  - fix-cleanup-CDS-nKlass-encoding
>
> src/hotspot/share/cds/archiveHeapWriter.hpp line 205:
> 
>> 203:   //    Since nKlass itself is 32 bit, our encoding range len is 4G, and since we set the base directly
>> 204:   //    at mapping start, these 4G are enough. Therefore, we don't need to shift at all (shift=0).
>> 205:   static constexpr int precomputed_narrow_klass_shift = 0;
> 
> "future" and "runtime" seem to mean the same thing. Maybe we should consistently use "runtime"?

Done

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PR Review Comment: https://git.openjdk.org/jdk/pull/14688#discussion_r1252601039